<button>
    <span class="box">
        Hover!
    </span>
</button>
<style>
/* From Uiverse.io by Cornerstone-04 - Tags: button */
.box {
  width: 140px;
  height: auto;
  float: left;
  transition: .5s linear;
  position: relative;
  display: block;
  overflow: hidden;
  padding: 15px;
  text-align: center;
  margin: 0 5px;
  background: transparent;
  text-transform: uppercase;
  font-weight: 900;
}

.box:before {
  position: absolute;
  content: '';
  left: 0;
  bottom: 0;
  height: 4px;
  width: 100%;
  border-bottom: 4px solid transparent;
  border-left: 4px solid transparent;
  box-sizing: border-box;
  transform: translateX(100%);
}

.box:after {
  position: absolute;
  content: '';
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  border-top: 4px solid transparent;
  border-right: 4px solid transparent;
  box-sizing: border-box;
  transform: translateX(-100%);
}

.box:hover {
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.5);
}

.box:hover:before {
  border-color: #262626;
  height: 100%;
  transform: translateX(0);
  transition: .3s transform linear, .3s height linear .3s;
}

.box:hover:after {
  border-color: #262626;
  height: 100%;
  transform: translateX(0);
  transition: .3s transform linear, .3s height linear .5s;
}

button {
  color: black;
  text-decoration: none;
  cursor: pointer;
  outline: none;
  border: none;
  background: transparent;
}
</style>
